A vibration damping device for railway vehicle is known to be interposed between a body and a truck of a railway vehicle, and to suppress vibration that acts on the railway vehicle and occurs in a right-and-left direction with respect to an advancing direction of the body.
JP 2010-65797 A discloses a vibration damping device for railway vehicle. The vibration damping device for railway vehicle includes a cylinder coupled to one of a truck and a body of a railway vehicle, a piston slidably inserted into the cylinder; a rod inserted into the cylinder and coupled to the piston and another one of the truck and the body, a rod-side chamber and a piston-side chamber partitioned by the piston inside the cylinder, a tank, a first on-off valve provided in a middle of a first passage for communicating between the rod-side chamber and the piston-side chamber, a second on-off valve provided in a middle of a second passage for communicating between the piston-side chamber and the tank, a pump for supplying a hydraulic fluid into the rod-side chamber, a discharge passage for connecting the rod-side chamber to the tank, and a variable relief valve provided in a middle of the discharge passage and capable of varying a valve opening pressure.
The vibration damping device for railway vehicle drives the pump, the first on-off valve, the second on-off valve, and the variable relief valve. Thus, the vibration damping device for railway vehicle exerts a thrust in both extending and contracting directions, and suppresses vibration of the body using the thrust. The vibration damping device for railway vehicle further includes a damper circuit so as to be capable of functioning as a passive damper under a state in which the first on-off valve and the second on-off valve are closed.